Interspecies comparative features of trichomes in Ocimum reveal insights for biosynthesis of specialized essential oil metabolites.

Ocimum species commonly referred to as "Tulsi" are well-known for their distinct medicinal and aromatic properties. The characteristic aroma of Ocimum species and cultivars is attributed to their specific combination of volatile phytochemicals mainly belonging to terpenoid and/or phenylpropanoid classes in their essential oils. The essential oil constituents are synthesized and sequestered in specialized epidermal secretory structures called as glandular trichomes. In this comparative study, inter- and intra-species diversity in structural attributes and profiles of expression of selected genes related to terpenoid and phenylpropanoid biosynthetic pathways have been investigated. This is performed to seek relationship of variations in the yield and phytochemical composition of the essential oils. Microscopic analysis of trichomes of O. basilicum, O. gratissimum, O. kilimandscharicum, and O. tenuiflorum (green and purple cultivars) revealed substantial variations in density, size, and relative proportions of peltate and capitate trichomes among them. The essential oil yield has been observed to be controlled by the population, dominance, and size of peltate and capitate glandular trichomes. The essential oil sequestration in leaf is controlled by the dominance of peltate glandular trichome size over its number and is also affected by the capitate glandular trichome size/number with variations in leaf area albeit at lower proportions. Comprehension and comparison of results of GC-MS analysis of essential oils showed that most of the Ocimum (O. basilicum, O. tenuiflorum, and O. gratissimum) species produce phenylpropanoids (eugenol, methyl chavicol) as major volatiles except O. kilimandscharicum, which is discrete in being monoterpenoid-rich species. Among the phenylpropanoid-enriched Ocimum (O. basilicum, O. gratissimum, O. tenuiflorum purple, O. tenuiflorum green) as well, terpenoids were important constituents in imparting characteristic aroma. Further, comparative abundance of transcripts of key genes of phenylpropanoid (PAL, C4H, 4CL, CAD, COMT, and ES) and terpenoid (DXS and HMGR) biosynthetic pathways was evaluated vis-à-vis volatile oil constituents. Transcript abundance demonstrated that richness of their essential oils with specific constituent(s) of a chemical group/subgroup was manifested by the predominant upregulation of phenylpropanoid/terpenoid pathway genes. The study provides trichomes as well as biosynthetic pathway-based knowledge for genetic improvement in Ocimum species for essential oil yield and quality.

Emerging Trends in Microwave Processing of Spices and Herbs.

Today, spices are integral part of our food as they provide sensory attributes such as aroma, color, flavour and taste to food. Further their antimicrobial, antioxidant, pharmaceutical and nutritional properties are also well known. Since spices are seasonal so their availability can be extended year round by adopting different preservation techniques. Drying and extraction are most important methods for preservation and value addition to spices. There are different techniques for drying of spices with their own advantages and limitations. A novel, non-conventional technique for drying of spices is use of microwave radiation. This technique proved to be very rapid, and also provide a good quality product. Similarly, there are a number of non-conventional extraction methods in use that are all, in principle, solid-liquid extractions but which introduce some form of additional energy to the process in order to facilitate the transfer of analytes from sample to solvent. This paper reviews latest advances in the use of microwave energy for drying of spices and herbs. Also, the review describes the potential application of microwave energy for extraction of essential oil/bioactive components from spices and herbs and the advantages of microwave-assisted process over the other extraction processes generally employed for extraction. It also showcases some recent research results on microwave drying/extraction from spices and herbs.

Experimental iron-inactivated Pasteurella multocida A: 1 vaccine adjuvanted with bacterial DNA is safe and protects chickens from fowl cholera.

Fowl cholera is a serious problem in large and small scale poultry production. The present study describes the development and testing of an inactivated whole-cell, low-cost, safe, and effective vaccine for fowl cholera based on a previous work (Vaccine 23:5590-5598). Pasteurella multocida A: 1 grown in the presence of low FeCl(3) concentrations, inactivated with higher concentrations of FeCl(3), and adjuvanted with bacterial DNA from P. multocida B: 2 containing immunostimulatory CpG motifs protect chickens with a lethal P. multocida A: 1 challenge. Chickens were immunized with two whole-cell inactivated vaccine doses at 4 weeks apart and challenged 4 weeks after booster immunization. Experimental vaccines were pure, easy injectable, and caused very little distress in chickens due to their aqueous consistency. Vaccines and bacterial DNA (bDNA) posed no safety problems when chickens were injected subcutaneously (s.c.) with a single, double, and overdose of these preparations. Immunized chickens produced systemic IgY antibodies (Ab) responses and vaccine adjuvanted with bDNA protected 100% chickens from lethal intrapertoneal (i.p.) P. multocida A: 1 challenge. This work suggests that use of bDNA as an adjuvant can improve the cost-effectiveness of inactivated veterinary vaccines for their use in developing countries. Our future studies will focus on safety and potency evaluation of experimental and current vaccines using bDNA as an adjuvant.

Salmonella typhimurium grown in iron-rich media, inactivated with ferric chloride and adjuvanted with homologous bacterial DNA is potent and efficacious vaccine in mice.

The present study describes our attempt to construct a novel vaccine formulation that affords full protection against murine typhoid under experimental conditions. Ferric chloride, 100mM, as inactivating agent, bacterial growth under iron-rich conditions and homologous bacterial DNA as adjuvant were used for construction of the experimental Salmonella typhimurium vaccine. The vaccine inoculated twice at 2 weeks interval in Swiss albino mice elicited statistically significant IgG levels when compared with non-adjuvanted and other control groups. All the mice inoculated with the novel vaccine withstood challenge with 50 LD(50) dose of S. typhimurium strain St 585. No significant safety problems were found in mice.